THE SURINAM TOAD. 27 
which inhabits Guiana and several provinces of Brazil. The most 
remarkable feature in this Batrachian is its manner of reproduction. 
It is Oviparous; and when the female has laid her eggs, the male 
takes them, and niles them on her back. The female, bearing the 
fertilised ova, reaches the marshes, and there immerses herself; but 
the skin which supports her future progeny soon becomes inflamed, 
erysipelatous inflammation follows, causing an irritation of the integu- 
ment, which continues till all are absorbed into the skin. 
The young are rapidly developed in these dorsal cells, and are 
extricated at a less advanced stage than almost any other vertebrate 
animal. After extrication, they grow rapidly, and the chief change 
of form is witnessed in the gills. As to the mother Batrachian, it is 
only after she has got rid of her progeny that she abandons her 
aquatic residence.* 
The Batrachians differ essentially from all other orders of Reptilia. 
They have no ribs; their skin is naked, being without scales. ‘The 
young, or Zadpoles, when first hatched, breathe by means of gills, being 
at this stage quite unlike their parents. These gills, or branchiz, 
disappear in the tailless Batrachians, as the Frogs and Toads. 
In the tadpoles the mouth is destitute of a tongue, this organ only 
making its appearance when the fore limbs are produced. ‘The 
habits also change: the tadpole no longer feeds on decomposing 
substances, and cannot live long immersed in water; the branchie 
disappear one after the other, by absorption, giving place to pul- 
monary vessels. The principal vascular arches are converted into 
the pulmonary artery, and the blood is diverted from the largest of 
the branchiz to the lungs. In the meantime the respiratory cavity is 
formed, the communicating duct advances with the elongation of the 
cesophagus, and at the point of communication the larynx is ultimately 
developed. The lungs themselves extend as simple elongated sacs, 
slightly reticulated on the inner surface backwards into the abdo- 
minal cavity. These receptacles being formed, air passes into and 
expands the cavity, and respiration is commenced, the fore limbs are 
liberated from the branchial chambers, and the first transformation is 
accomplished. 
_The alleged venomous character of the Common Toad has been 
altogether rejected by many naturalists ; but Dr. Davy found that 
_* The same phenomena occur, with certain variations, in some other American 
Batrachians, as the Wototrema marsupiatum of Mexico, and the Wotodelphys ovifera 
of Venezuela. In the Altes obstetricans of France, Switzerland, and the Rhine 
district, the ova (about sixty in number) adhere to the hind-legs of the inale 
parent !—Ep. 
